In general, a transmitter outputs visible light by using a Light Emitting Diode (LED), a Laser Diode (LD), or the like as a light source, and a receiver processes the output visible light by using a Photo Detector (PD) and the like to perform visible light communication.
Interest in visible light communication has grown in recent times due to depletion of frequencies in the Radio Frequency (RF) band, visible light communication's crosstalk possibility between various wireless communication technologies, an increase in demand of communication security, and the like. Further, together with a rapid spread of LED lighting, the use of visible light communication has also rapidly increased.
The visible light communication is safe, and has a wide use band and is not regulated and to be freely used, and further, it is possible to recognize a place which light reaches or a direction in which light moves, so that there is an advantage in that it is possible to accurately recognize a reception range of information. Accordingly, visible light communication is reliable in terms of security. Further, visible light communication is advantageous due to its lower power consumption levels.
Accordingly, visible light communication is applicable to hospitals, airplanes, and the like in which the use of the RF is limited, and may provide additional information services using an electronic display board.
In the meantime, a portable mobile terminal includes additional functions, such as a message transceiving function, a wireless Internet function, and a positioning service function, in addition to a simple voice communication function for convenience of the user.